That wasn't my claim. My claim was that they're using much of the same chemical and culinary science. For example: salt = good, more salt = usually better! Similarly, people can and do gorge themselves on gourmet food. God knows I've done so myself a few times.
You don't get sick of them, or full from them...
I invite you to test this claim with a 17oz bag!
Plenty of people find themselves completely satisfied with a reasonable quantity of Doritos. It's also an enjoyable experience for them. This food engineering is designed to make that experience more enjoyable. They're not physically addictive in any meaningful sense. If your threshold for "moral tenuousness" is the potential to cause harm because you've produced something tasty enough that people have more than is healthy for them, then you'd have to string up a whole bunch of brewers and winemakers, too. Which would be too bad.